package com.hmdp.service.impl;

//import cn.hutool.core.io.resource.ClassPathResource;
import cn.hutool.core.bean.BeanUtil;
import cn.hutool.core.util.BooleanUtil;
import com.hmdp.dto.Result;
import com.hmdp.entity.VoucherOrder;
import com.hmdp.mapper.VoucherOrderMapper;
import com.hmdp.service.ISeckillVoucherService;
import com.hmdp.service.IVoucherOrderService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.utils.RedisIdWorker;
import com.hmdp.utils.UserHolder;
import lombok.extern.slf4j.Slf4j;
import org.redisson.api.RLock;
import org.redisson.api.RedissonClient;
import org.redisson.reactive.MapReactiveIterator;
import org.springframework.aop.framework.AopContext;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.connection.stream.*;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.PostConstruct;
import javax.annotation.Resource;
import java.time.Duration;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Slf4j
@Service
public class VoucherOrderServiceImpl extends ServiceImpl<VoucherOrderMapper, VoucherOrder> implements IVoucherOrderService {
    @Resource
    private ISeckillVoucherService seckillVoucherService;
    @Resource
    private RedisIdWorker redisIdWorker;
    @Resource
    private StringRedisTemplate stringRedisTemplate;

    @Resource
    private RedissonClient redissonClient;

    private static final DefaultRedisScript<Long> SECKILL_SCRIPT;
    static {
        SECKILL_SCRIPT = new DefaultRedisScript<>();
        SECKILL_SCRIPT.setLocation(new ClassPathResource("seckill.lua"));
        SECKILL_SCRIPT.setResultType(Long.class);
    }


    private static final ExecutorService SECKILL_ORDER_EXECUTOR = Executors.newSingleThreadExecutor();

    private class VoucherOrderHandler implements Runnable {
        String queueName = "stream.orders";
        @Override
        public void run() {
            while (true) {
                try {
                    // 0.初始化stream
                    initStream();
                    // 1.获取消息队列中的订单信息
                    List<MapRecord<String,Object,Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1","c1"),
                            StreamReadOptions.empty().count(1).block(Duration.ofSeconds(2)),
                            StreamOffset.create(queueName, ReadOffset.lastConsumed())
                    );
                    // 2. 判断消息获取是否成功
                    if(list == null || list.isEmpty()){
                        // 如果获取失败，说明没有消息，继续下一次循环
                        continue;
                    }
                    // 3.解析消息中的订单信息
                    MapRecord<String, Object, Object> record = list.get(0);
                    Map<Object, Object> values = record.getValue();
                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(values, new VoucherOrder(), true);
                    // 4.如果获取成功，可以下单
                    handleVoucherOrder(voucherOrder);
                    // 5.ACK确认
                    stringRedisTemplate.opsForStream().acknowledge(queueName,"g1",record.getId());
                } catch (Exception e) {
                    log.error("处理订单异常", e);
                    handlePendingList();
                }
            }
        }

        public void initStream(){
            Boolean exists = stringRedisTemplate.hasKey(queueName);
            if (BooleanUtil.isFalse(exists)) {
                log.info("stream不存在，开始创建stream");
                // 不存在，需要创建
                stringRedisTemplate.opsForStream().createGroup(queueName, ReadOffset.latest(), "g1");
                log.info("stream和group创建完毕");
                return;
            }
            // stream存在，判断group是否存在
            StreamInfo.XInfoGroups groups = stringRedisTemplate.opsForStream().groups(queueName);
            if(groups.isEmpty()){
                log.info("group不存在，开始创建group");
                // group不存在，创建group
                stringRedisTemplate.opsForStream().createGroup(queueName, ReadOffset.latest(), "g1");
                log.info("group创建完毕");
            }
        }

        private void handlePendingList(){
            while (true) {
                try {
                    // 1.获取pending-list中的订单信息
                    List<MapRecord<String,Object,Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1","c1"),
                            StreamReadOptions.empty().count(1),
                            StreamOffset.create(queueName, ReadOffset.from("0"))
                    );
                    // 2. 判断消息获取是否成功
                    if(list == null || list.isEmpty()){
                        // 如果获取失败，说明pending-list没有消息，结束循环
                        break;
                    }
                    // 3.解析消息中的订单信息
                    MapRecord<String, Object, Object> record = list.get(0);
                    Map<Object, Object> values = record.getValue();
                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(values, new VoucherOrder(), true);
                    // 4.如果获取成功，可以下单
                    handleVoucherOrder(voucherOrder);
                    // 5.ACK确认
                    stringRedisTemplate.opsForStream().acknowledge(queueName,"g1",record.getId());
                } catch (Exception e) {
                    log.error("处理pending-list订单异常", e);
                    try {
                        Thread.sleep(20);
                    } catch (InterruptedException interruptedException) {
                        interruptedException.printStackTrace();
                    }
                }
            }
        }
    }
    @PostConstruct
    private void init(){
        SECKILL_ORDER_EXECUTOR.submit(new VoucherOrderHandler());
    }
//    private BlockingQueue<VoucherOrder> orderTasks = new ArrayBlockingQueue<>(1024 * 1024);
//    private class VoucherOrderHandler implements Runnable{
//        @Override
//        public void run() {
//            while(true){
//                try {
//                    // 1.获取队列中的订单信息
//                    VoucherOrder voucherOrder = orderTasks.take();
//                    // 2.创建订单
//                    handleVoucherOrder(voucherOrder);
//                } catch (Exception e) {
//                   log.error("处理订单异常",e);
//                }
//            }
//        }

    private void handleVoucherOrder(VoucherOrder voucherOrder) {
        // 1.获取用户
        Long userId = voucherOrder.getUserId();
        // 2.创建锁对象
        RLock lock = redissonClient.getLock("lock:order:" + userId);
        // 3.获取锁
        boolean isLock = lock.tryLock();
        // 4.判断是否获取锁成功
        if(!isLock){
            // 获取锁失败，返回错误或重试
            log.error("不允许重复下单");
            return ;
        }
        try{
            // 获取代理对象（事务）
            proxy.createVoucherOrder(voucherOrder);
        }finally {
            // 释放锁
            lock.unlock();
        }
    }

    @Override
    public Result seckillVoucher(Long voucherId) {
        Long userId = UserHolder.getUser().getId();
        long orderId = redisIdWorker.nextId("order");
        // 1.执行lua脚本
        Long result = stringRedisTemplate.execute(
                SECKILL_SCRIPT,
                Collections.emptyList(),
                voucherId.toString(), userId.toString(), String.valueOf(orderId)
        );
        int r = result.intValue();
        // 2.判断结果是否为0
        if (r != 0) {
            // 2.1.不为0 ，代表没有购买资格
            return Result.fail(r == 1 ? "库存不足" : "不能重复下单");
        }
        // 3.获取代理对象
        proxy = (IVoucherOrderService) AopContext.currentProxy();
        // 4.返回订单id
        return Result.ok(orderId);
    }

    private IVoucherOrderService proxy;
//    @Override
//    public Result seckillVoucher(Long voucherId) {
//        // 获取用户
//        Long userId = UserHolder.getUser().getId();
//        // 获取订单id
//        long orderId = redisIdWorker.nextId("order");
//        // 1.执行lua脚本
//        Long result = stringRedisTemplate.execute(
//                SECKILL_SCRIPT,
//                Collections.emptyList(),
//                voucherId.toString(),
//                userId.toString(),
//                String.valueOf(orderId)
//        );
//        // 2.判断结果是为0
//        int r = result.intValue();
//        if(r != 0){
//            // 2.1.不为0,代表没有购买资格
//            return Result.fail(r == 1 ? "库存不足" : "不能重复下单");
//        }
//        // 2.2.为0，有购买资格，把下单信息保存到阻塞队列
//        VoucherOrder voucherOrder = new VoucherOrder();
//        // 2.3.订单id
//        long orderId = redisIdWorker.nextId("order");
//        voucherOrder.setId(orderId);
//        // 2.4.用户id
//        voucherOrder.setUserId(userId);
//        // 2.5.代金券id
//        voucherOrder.setVoucherId(voucherId);
//        // 2.6.放入阻塞队列
//        orderTasks.add(voucherOrder);
//        // 3.获取代理对象
//        proxy = (IVoucherOrderService) AopContext.currentProxy();
//        // TODO 保存阻塞队列
//
//        // 4.返回订单id
//        return Result.ok(orderId);
//    }



//    @Override
//    @Transactional
//    public Result seckillVoucher(Long voucherId) {
//        // 1. 查询优惠券
//        SeckillVoucher voucher = seckillVoucherService.getById(voucherId);
//        // 2. 判断秒杀是否开始
//        if (voucher.getBeginTime().isAfter(LocalDateTime.now())){
//            // 尚未开始
//            return Result.fail("秒杀尚未开始");
//        }
//        // 3. 判断秒杀是否结束
//        if ( voucher.getEndTime().isBefore(LocalDateTime.now())){
//            // 已经结束
//            return Result.fail("秒杀已经结束");
//        }
//        // 4. 判断库存是否充足
//        if(voucher.getStock() < 1){
//            // 库存不足
//            return Result.fail("库存不足");
//        }
//        Long userId = UserHolder.getUser().getId();
//        // 创建锁对象
////        SimpleRedisLock lock = new SimpleRedisLock("order:" + userId, stringRedisTemplate);
//        RLock lock = redissonClient.getLock("lock:order:" + userId);
//        // 获取锁
//        boolean isLock = lock.tryLock();
//        // 判断获取锁是否成功
//        if (!isLock){
//            // 获取锁失败，返回错误或重试
//            return Result.fail("不允许重复下单");
//        }
//        try {
//            //获取代理对象(事务)
//            IVoucherOrderService proxy = (IVoucherOrderService) AopContext.currentProxy();
//            return proxy.createVoucherOrder(voucherId);
//        } finally {
//            // 释放锁
//            lock.unlock();
//        }
//    }

    @Transactional
    public void createVoucherOrder(VoucherOrder voucherOrder){
        // 5. 一人一单
        Long userId = voucherOrder.getUserId();
        // 5.1 查询订单
        int count = query().eq("user_id", userId).eq("voucher_id", voucherOrder).count();
        // 5.2 判断是否存在
        if (count > 0) {
            log.error("该用户已经购买过一次了！");
            return ;
        }
        // 6. 扣减库存
        boolean success = seckillVoucherService.update()
                .setSql("stock = stock - 1")
                .eq("voucher_id", voucherOrder) // set stock = stock - 1
                .gt("stock", 0) // where id = ? and stock = ?
                .update();
        if (!success) {
            // 扣减失败
            log.error("库存不足！");
            return ;
        }
        save(voucherOrder);
    }
}